Modeling for Development Capacity of Dieng Geothermal Field, Indonesia

Abstract

Dieng geothermal field is volcanic geothermal reservoir located in Central Java, Indonesia, about 120 km from Semarang the capital city of Central Java Province. Since 2002, Geo Dipa Energi start to operate commercially Dieng Unit 1 with installed capacity 60 MW and the generated electricity is transferred to the Java – Madura – Bali interconnection system to support the electricity needs in this interconnection system. According to the Statistic PLN 2013, the electricity needs in Java at the end of December 2013 is about 26,768 MW (78.3% from total needs in Indonesia). And about 1.67% of total electricity generated in Indonesia is generated from geothermal power plant where mostly located in Java. After more than 12 years operation Dieng Unit 1, new data from production monitoring, downhole logging, sampling and analysis of the geothermal chemical fluid, combined with initial data measurements and geoscience interpretation were integrated to update the conceptual model and 3D model of Dieng geothermal field. The numerical simulation model was developed to evaluate the reservoir performance since exploitation of Dieng Unit 1 and to assess the reservoir capacity to develop Dieng Unit 2 and 3. The simulation using Petrasim V.5.2 pre and post processor for the TOUGH2 V.2.0 (Pruesss et all., 1999) numerical reservoir simulator developed at LBNL, Barkeley (USA). As TOUGH2 EOS module, EWAS (Battistelli et all., 1997) for mixtures of water-NaCl-CO2 has been used.